Substituted phenoxyalkanecarboxylic acid esters

ABSTRACT

Novel substituted phenoxyalkanecarboxylic acid esters of the formula ##STR1## in which R 1  and R 2 , independently of one another, are a hydrogen atom, a halogen atom, a lower alkyl group or a nitro group, or 
     R 1  and R 2 , together with the benzene ring to which they are bonded, are a naphthalene ring, 
     R 3  and R 4 , independently of one another, are a hydrogen atom or a methyl group, 
     n is 1 or 2, 
     m is 0 or 1, 
     X is an oxygen atom, a sulfur atom, a sulfonyl group or a group of the formula ##STR2##  in which R 6  is a lower alkyl group, R 5  is a hydrogen atom or a halogen atom, and 
     Y is an oxygen atom or a sulfur atom, and the use of the new compounds as herbicides.

This is a division of application Ser. No. 661,622 filed Oct. 17, 1984now U.S. Pat. No. 4,666,503.

The invention relates to certain new substituted phenoxyalkanecarboxylicacid esters, to herbicidal compositions containing such compounds and tomethods for combating weeds utilizing such compounds.

It has already been disclosed that certainbenzothiazolyl-oxy-phenoxy-propionates have good herbicidal properties(see U.S. Pat. No. 4,130,413 and JP-OS (Japanese PublishedSpecification) No. 40,767-1978). Thus theethyl-2{4-[(6-chloro-2-benzothiazolyl)-oxy]-phenoxy}-propionate can beused for combating weeds. However, the action of this compound is notalways completely satisfactory, especially when small amounts and lowconcentrations are applied.

The present invention now provides, as new compounds the substitutedphenoxyalkanecarboxylic acid esters of the general formula ##STR3## inwhich

R¹ and R², independently of one another, represent a hydrogen atom, ahalogen atom, a lower alkyl group or a nitro group, or

R¹ and R², together with the benzene ring to which they are bonded,represent a naphthalene ring,

R³ and R⁴, independently of one another, represent a hydrogen atom or amethyl group,

n represents 1 or 2,

m represents 0 or 1,

X represents an oxygen atom, a sulfur atom, a sulfonyl group or a groupof the formula ##STR4## in which

R⁶ represents a lower alkyl group,

R⁵ represents a hydrogen atom or a halogen atom, and

Y represents an oxygen atom or a sulfur atom.

The substituted phenoxyalkanecarboxylic acid esters of the formula (I)contain at least one asymetrically substituted carbon atom and cantherefore occur in different enantiomeric forms. The invention relatesboth to the possible individual isomers and to mixtures of theseisomers.

The substituted phenoxyalkanecarboxylic acid esters of the formula (I),can be prepared by a process which comprises

(a) reacting a compound of the general formula ##STR5## in which

R⁵ and Y have the meanings given above and Hal represents a halogenatom, with a compound of the general formula ##STR6## in which

R¹, R², R³, R⁴, m, n and X have the meanings given above and

M represents a hydrogen atom or an alkali metal atom,

or

(b) reacting a compound of the general formula ##STR7## in which

R⁵, M and Y have the meanings given above, with a compound of thegeneral formula ##STR8## in which

R¹, R², R³, R⁴, X, m, n and Hal have the meanings given above,

or

(c) reacting a compound of the general formula ##STR9## in which

R⁵, Y and Hal have the meanings given above, with a compound of thegeneral formula ##STR10## in which

R¹, R², R³, R⁴, M, X, m and n have the meanings given above,

or

(d) reacting a compound of the general formula ##STR11## in which

R¹, R², R³, R⁴, R⁵, Y, m and n have the meanings given above, withhydrogen peroxide.

The present invention also provides herbicidal compositions comprisingas active ingredients substituted phenoxyalkanecarboxylic acid esters ofthe general formula (I). In an additional aspect, the present inventionprovides a method of combating weeds by applying a substitutedphenoxyalkanecarboxylic acid ester of the general formula (I) to theweeds or to their habitat.

Surprisingly, the compounds according to the present invention, whichhave not previously been described in the literature, show an excellentherbicidal activity and are particularly useful for selectivelycombating a wide range of weeds, such as graminaceous weeds, withoutcausing substantial phytotoxicity on useful farm crops, such as rice. Itis particularly surprising that the compounds according to thisinvention also exhibit a better herbicidal activity than theethyl-2-{4-[(6-chloro-2-benzothiazolyl)-oxy]phenoxy}-propionate, whichis known from the state of art and is a closely related compoundchemically and from the point of view of its action.

The compounds according to the present invention are stucturallycharacterised by the fact that a group of the formula ##STR12## isattached to a benzo-azolyloxy-phenoxy-propionic acid moiety via an esterlinkage.

Preferred compounds according to the present invention are thosesubstituted phenoxyalkanecarboxylic acid esters of the general formula(I), in which

R¹ represents hydrogen, fluorine, chorine, bromine, iodine, alkyl with 1to 4 carbon atoms or nitro,

R² represents hydrogen, fluorine, chlorine, bromine, iodine, alkyl with1 to 4 carbon atoms or nitro,

or

R¹ and R², together with the benzene ring to which they are bonded,represent a naphthalene ring,

R³ represents hydrogen or methyl,

R⁴ represents hydrogen or methyl,

m represents 0 or 1,

n represents 1 or 2,

X represents oxygen, sulfur, sulfonyl or a group of the formula##STR13## in which

R⁶ represents alkyl with 1 to 4 carbon atoms,

R⁵ represents hydrogen, fluorine, chlorine, bromine and iodine, and

Y represents oxygen or sulfur.

Particularly preferred compounds according to the present invention arethose substituted phenoxyalkanecarboxylic acid esters of the generalformula (I), in which

R¹ represents hydrogen, fluorine, chlorine, bromine, methyl, ethyl,n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert.-butyl ornitro,

R² represents hydrogen, fluorine, chlorine, bromine, methyl, ethyl,n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert.-butyl ornitro, or

R¹ and R², together with the benzene ring to which they are bonded,represent a naphthalene ring,

R³ represents hydrogen or methyl,

R⁴ represents hydrogen or methyl,

m represents 0 or 1,

n represents 1 or 2,

X represents oxygen, sulfur, sulfonyl or a group of the formula##STR14## in which

R⁶ represents methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,sec-butyl or tert.-butyl,

R⁵ represents hydrogen, fluorine, chlorine, or bromine, and

Y represents oxygen or sulfur.

As already mentioned above, the compounds according to the inventioncontain at least one asymmetrically substituted carbon atom in the sidechain, and can therefore occur in two enantiomeric forms. In the formulabelow, the asymmetrically substituted carbon atom is designated by an(*). ##STR15##

The invention relates both to the particular racemates and to the R andS enantiomers.

In the present context, R enantiomers (S enantiomers) are understood ineach case as meaning those optically active compounds which have the Rconfiguration (S configuration) at the asymmetrically substituted carbonatom of the propionic acid unit.

Particularly preferred R enantiomers are those of the substitutedphenoxyalkanecarboxylic acid esters of the formula (I) in which R¹, R²,R³, R⁴, R⁵, X, Y, m and n have the meanings which are stated above asbeing particularly preferred.

The course of process variant (a) according to the present invention canbe illustrated by the following general reaction scheme: ##STR16##

If specific starting materials are used, the course of process variant(a) according to the present invention can be represented by thefollowing equation: ##STR17##

Formula (II) gives an unambiguous definition of the compounds requiredas starting materials in process variant (a) according to the invention.In this formula, R⁵ and y preferably represent those radicals which havealready been mentioned as preferred therefor in connection with thedescription of the substances of the formula (I). Hal preferablyrepresents chlorine or bromine.

The following may be mentioned as examples of compounds of the formula(II):

2-chlorobenzothiazole,

2-bromobenzothiazole,

2-chlorobenzoxazole,

2-bromobenzoxazole, and

6-chloro-2-bromobenzothiazole.

Formula (III) provides a general definition of the compounds required asfurther starting materials in process variant (a) according to theinvention. In this formula, R¹, R², R³, R⁴, X, m and n preferablyrepresent those radicals and indices, which have already been mentionedas preferred therefor in connection with the description of thesubstances of the formula (I). M preferably represents a hydrogen atom,a lithium, potassium or a sodium atom.

The following may be mentioned as examples of compounds of the formula(III):

2-(2-chlorobenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(4-chlorobenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(2,6-dichlorobenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(2-fluorobenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(2-methylbenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(1-naphthylmethoxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(3-nitrobenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(N-benzyl-N-isopropylamino)ethyl 2-(4-hydroxyphenoxy)-propionate,

2-benzyloxyethyl 2-(4-hydroxyphenoxy)propionate,

2-(α-methylbenzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(2-benzyloxyethoxy)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(1-methyl-2-benzyloxy)ethyl 2-(4-hydroxyphenoxy)propionate,

3-benzyloxypropyl 2-(4-hydroxyphenoxy)propionate,

2-benzylthioethyl 2-(4-hydroxyphenoxy)propionate,

2-(2-chlorobenzylthio)ethyl 2-(4-hydroxyphenoxy)propionate,

2-(2-chlorobenzylsulfonyl)ethyl 2-(4-hydroxyphenoxy)-propionate, and

2-(N-benzyl-N-methylamino)ethyl 2-(4-hydroxyphenoxy)-propionate, and thecorresponding lithium, sodium and potassium salts.

Reaction variant (a) according to the present invention is preferablycarried out in the presence of a solvent or diluent. For this purpose,any inert solvents and diluents may be employed.

Examples of such solvents and diluents include water; aliphatic,alicyclic and aromatic hydrocarbons--each of which may optionally bechlorinated (such as hexane, cyclohexane, petroleum ether, ligroin,benzene, toluene, xylene, methylene chloride, chloroform, carbontetrachloride, ethylene chloride, tri-chloroethylene, andchlorobenzene), ethers (such as diethyl ether, methyl ethyl ether,di-isopropyl ether, dibutyl ether, propylene oxide, dioxane, andtetrahydrofuran), ketones (such as acetone, methyl ethyl ketone, methylisopropyl ketone, and methyl isobutyl ketone, nitriles (such asacetonitrile, propionitrile, and acrylonitrile), alcohols (such asmethanol, ethanol, iso-propanol, butanol, and ethylene glycol), esters(such as ethyl acetate and amyl acetate), acid amides (such asdimethylformamide and diemthylacetamide), sulfones and sulfoxides (suchas dimethylsulfoxide and sulfolane) and bases (such as pyridine).

The reaction variant (a) is preferably carried out in the presence ofacid-binding agent. As examples of such acid-binding agents, there maybe mentioned hydroxides, carbonates, bicarbonates and alcoholates ofalkali metals, and tertiary amines such as triethylamine,diethylaniline, pyridine,

Reaction variant (a) can be carried out over a wide range oftemperatures. Generally, it is carried out at a temperature between -20°C. and the boiling point of the reaction mixture, preferably between 0°C. and 100° C.

This reaction variant (a) is preferably carried out under ambientpressure, although it can be effected under elevated or reducedpressure.

The course of process variant (b) according to the present invention canbe illustrated by the following general reaction scheme: ##STR18##

If specific starting materials are used, the course of process variant(b) according to the present invention can be represented by thefollowing equation: ##STR19##

Formula (IV) gives an unambiguous definition of the compounds, which arerequired as starting materials in process variant (b) according to theinvention. In this formula, R⁵ and Y preferably represent those radicalswhich have already been mentioned as preferred therefor in connectionwith the description of the substances of the formula (I). M preferablyrepresents a hydrogen atom, a lithium, potassium or a sodium atom.

Formula (V) provides a general definition of the compounds, which arealso required as starting materials in process variant (b) according tothe invention. In this formula, R¹, R², R³, R⁴, X, m and n preferablyrepresent those radicals and indices, which have already been mentionedas preferred therefor in connection with the description of thesubstances of the formula (I). Hal preferably represents chlorine orbromine.

In carrying out reaction variant (b), any of the inert solvents ordiluents as described hereinbefore for reaction variant (a) arepreferably used to obtain the end products with high purity in highyield. Likewise, reaction variant (b) is preferably carried out in thepresence of an acid binding agent as described hereinbefore for reactionvariant (a).

Reaction variant (b) can be carried out over a wide range oftemperatures. Generally, it is carried out at a temperature between -20°C. and the boiling point of the reaction mixture, preferably between 0°C. and 100° C.

The reaction variant (b) is preferably carried out under ambientpressure, although it can be effected under elevated or reducedpressure.

The course of process variant (c) according to the present invention canbe illustrated by the following general reaction scheme: ##STR20##

If specific starting materials are used, the course of process variant(c) according to the present invention can be represented by thefollowing equation: ##STR21##

Formula (VI) gives an unambiguous definition of the compounds requiredas starting materials in process variant (c) according to the invention.In this formula, R⁵ and Y preferably represent those radicals which havealready been mentioned as preferred therefor in connection with thedescription of the substances of the formula (I). Hal preferablyrepresents chlorine or bromine.

Formula (VII) provides a general definition of the compounds required asfurther starting materials in process variant (c) according to theinvention. In this formula, R¹, R², R³, R⁴, X, m and n preferablyrepresent those radicals and indices, which have already been mentionedas preferred therefor in connection with the description of thesubstances of the formula (I). M preferably represents a hydrogen atom,a lithium, sodium or a potassium atom.

In carrying out reaction variant (c), any of the inert solvents ordiluents as described hereinbefore for reaction variant (a), exceptalcohols, are preferably used to obtain the end products with highpurity in high yield. Likewise, reaction variant (c) is preferablycarried out in the presence of an acid-binding agent as describedhereinbefore for reaction variant (a).

Reaction variant (c) can be carried out over a wide range oftemperatures. Generally, it is carried out at a temperature between -20°C. and the boiling point of the reaction mixture, preferably between 0°C. and 100° C.

The reaction variant (c) is preferably carried out under ambientpressure, although it can be effected under elevated or reducedpressure.

The course of process variant (d) according to the present invention canbe illustrated by the following general reaction scheme: ##STR22##

If specific starting materials are used, the course of process variant(d) according to the present invention can be represented by thefollowing equation: ##STR23##

In carrying out reaction variant (d), any of the inert solvents ordiluents as described hereinbefore for reaction variant (a) can be used.

Reaction variant (d) can be carried out over a wide range oftemperatures. Generally, it is carried out at a temperature between -20°C. and the boiling point of the reaction mixture, preferably between 0°C. and 100° C.

The reaction variant (d) is preferably carried out under ambientpressure, although it can be effected under elevated or reducedpressure.

The active compounds of the formula (I) according to the presentinvention show excellent selective herbicidal activity. They can beapplied either before or after emergence of the plants. They arepreferably applied before emergence of the plants, that is to say by thepre-emergence method. They can also be incorporated into the soil beforesowing.

Since the active compounds according to the present invention showlittle or no toxicity towards warmblooded animals and show goodselectivity for agricultural plants, that is, cause no phytotoxicity foragricultural plants, they can be conveniently used as herbicides forcontrolling weeds, particularly for the control of graminaceous weeds.By "weeds" in the broadest sense there are meant plants growing inplaces where they are not desired.

The active compounds according to the present invention may be used, forexample, co combat the following plants:

Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi,

Echinochloa crus-galli P. Beauv. var. caudata Kitagawa,

Echinochloa crus-galli P. Beauv. var. formosensis Ohwi,

Sacciolepis indica Chase var. oryzetorum Ohwi,

Glyceria acutiflora torr.,

Glyceria natans Komorov.,

Polypogon fugax Steud.,

Panicum bisulcatum Thunb., and

Paspalum distichum L.,

Echinochloa crus-galli P. Beauv.,

Agropyron tsukushiense Ohwi var. transiens Ohwi,

Poa annua L.,

Alopecurus aequalis Sobol. var. amurensis Ohwi,

Eleusine indica Gaertn.,

Digitaria adscendens Henr.,

Cynodon dactylon Pers.,

Setaria viridis P. Beauv.,

Setaria glauca P. Beauv., and

Avena fatua L.

In addition, they also show excellent herbicidal and regrowth-controleffects on, for example, perennial weeds, such as Johnson grass andCynodon dactylon.

The active compounds according to the present invention may be used asselective herbicides in many cultures. As examples the followingcultures may be mentioned: beans, cotton, carrot, potato, beet, cabbage,mustard, peanut, radish, tobacco, tomato and cucumber.

The active compounds according to the present invention can be convertedinto customary formulations using agricultural acceptable adjuvants bymethods generally practiced in the production of agricultural chemicals,In actual use, the herbicidal compositions in various forms are appliedeither directly or after diluting them with water to the desiredconcentrations. Examples of the agricultural acceptable adjuvants, asreferred to herein, are diluents (solvents, extenders, carriers),surfaceactive agents (solubilizing agents, emulsifiers, dispersants,wetting agents), stabilizers, stickers, aerosol propellants, andsynergists.

Examples of the solvents are water, and organic solvents, for examplehydrocarbons (e.g., n-hexane, petroleum ether, naphtha, petroleumfractions (e.g. paraffin waxes, kerosine, light oils, middle oils, heavyoils), benzene, toluene, and xylenes), halogenated hydrocarbons (e.g.,methylene chloride, carbon tetrachloride, trichloroethylene, ethylenedichloride, chlorobenzene and chloroform), alcohols (e.g. methylalcohol, ethyl alcohol, propyl alcohol, and ethylene glycol), ethers(e.g., ethyl ether, ethylene oxide and dioxane), alcohol ethers (e.g.,ethylene glycol monomethyl ether), ketones (e.g. acetone andisophorone), esters (e.g., ethyl acetate and amyl acetate), amides (e.g.dimethylformamide and dimethylacetamide) and sulfoxides (e.g., dimethylsulfoxide).

Examples of the extenders or carriers include inorganic powders, forexamples slaked lime, magnesium lime, gypsum, calcium carbonate, silica,perlite, pumice, calcite, diatomaceous earth, amorphous silica, alumina,zeolites, and clay minerals (e.g., pyrophylite, talc, montmorillonite,beidelite, vermiculite, kaolinite and mica); vegetable powders such ascereal powders, starches, processed starches, sugar, glucose and crushedstalks of plants, and powders of synthetic resins such as phenolicresins, urea resins, and vinyl chloride resins.

Examples of the surface-active agents include anionic surface-activeagents such as alkylsulfuric acid esters (e.g., sodium laurylsulfate),arylsulfonic acid salts (e.g., alkylarylsulfonic acid salts and sodiumalkylnaphthalenesulfonates), succinic acid salts and salts of sulfuricacid esters of polyethylene glycol alkylaryl ethers; cationicsurface-active agents such as alkylamines (e.g., laurylamine, stearyltrimethyl ammonium chloride and alkyl dimethylbenzyl ammonium chloride)and polyoxyethylene alkylamines; nonionic surface-active agents such aspolyoxyethylene glycol ethers (e.g. polyoxyethylene alkylaryl ethers andthe condensation products thereof), polyoxyethylene glycol esters (e.g.,polyoxyethylene fatty acid esters), and polyhydric alcohol esters (e.g.polyoxyethylene sorbitan monolaurate); and amphoteric surface-activeagents.

Examples of other adjuvants include stabilizers; stickers (e.g.agricultural soaps, casein lime, sodium alginate, polyvinyl alcohols,vinyl acetate-type adhesives and acrylic adhesives); aerosol propellants(such as trichlorofluoromethane, dichlorofluoromethane,1,2,2-trichloro-1,1,2-trifluoroethane, chlorobenzene, LNG, and lowerethers); combustion controlling agents for fumigants (such as nitrites,zinc powder, and dicyandiamide); oxygen-yielding agents (such aschlorates); effect-prolonging agents; dispersion stabilizers (such ascasein, tragacanth, carboxymethyl cellulose (CMC), and polyvinyl alcohol(PVA)); and synergists.

The active compounds according to this invention can be converted intothe customary formulations, such as emulsifiable concentrates, oils,wettable powders, soluble powders, suspensions, dusts, granules andpulverulent compositions. These formulations may be produced in knownmanner.

The amount of active compound in ready-to-use preparations can varywidely according to circumstance. However, it is in general from 0.001to about 100 percent by weight of active compound, preferably from about0.005 to 95 percent by weight.

In actual use, the suitable amount of the active compound in theaforesaid compositions of various forms and ready-to-use preparationsis, for example, about 0.01 to about 95% by weight, preferably about0.05 to about 60% by weight.

The content of the active ingredient can be properly varied dependingupon the form of the preparation or composition, the method, purpose,time and locus of its application, the state of occurrence of weeds,etc.

If required, the compound of this invention may be used further incombination with other agricultural chemicals, for example insecticides,fungicides, miticides, nematocides, antiviral agents, other herbicides,plant growth regulators and attractants (e.g., organophosphorus estercompounds, carbamate compounds, dithio (or thiol) carbamate compounds,organic chlorine compounds, dinitro compounds, organic sulfur or organometallic compounds, antibiotics, substituted diphenyl ether compounds,urea, compounds, and triazine compounds), and/or fertilizers.

Various compositions and ready-to-use preparations containing theaforesaid active ingredients can be applied by various methods generallypracticed in the field of agricultural application, for exampledispersing (liquid spraying, misting, atomizing, dust dispersing,granule dispersing, water surface application and pouring); and soilapplication (mixing with the soil, and sprinkling). They can also beused by the so-called ultralow volume spraying method. According to thismethod, the active ingredient may be included in an amount of 100%.

The rate of application per unit area is, for example, about 0.1 toabout 5.0 kg, preferably about 0.2 to about 2.0 kg, per hectare. Inspecial cases, however, it may, and sometimes should, be outside thespecified range.

The present invention also provides a herbicidal composition containingas active ingredient a compound of the present invention in admixturewith a solid diluent or carrier or in admixture with a liquid diluent orcarrier containing a surface-active agent.

The present invention also provides a method of combating weeds whichcomprises applying to the weeds or to a habitat thereof, a compound ofthe present invention alone or in the form of a composition containingas active ingredient a compound of the present invention in admixturewith a diluent or carrier.

It will be seen that the usual methods of providing a harvested crop maybe improved by the present invention.

The following examples illustrate the present invention specifically. Itshould be noted, however, that the invention is not limited to thesespecific examples alone.

PREPARATIVE EXAMPLES EXAMPLE 1 ##STR24##

38.5 g of 2-(2,6-dichlorobenzyloxy)ethyl 2-(4-hydroxyphenoxy)-propionatewere dissolved in 200 ml of dimethylformamide and 15.2 g of potassiumcarbonate were added to the solution. The mixture was stirred at 80° C.for 1 hour. A solution of 18.6 g of 2-chlorobenzothiazole in 50 ml ofdimethylformamide was added dropwise at this temperature to theresulting mixture. After the addition, the mixture was stirred at thesame temperature for 2 hours to complete the reaction. The reactionmixture was poured onto ice water, and the separated oily product wasextracted with toluene. The toluene layer was washed successively with a1% aqueous solution of sodium hydroxide and water, and then toluene wasevaporated under reduced pressure to give 43.5 g of2-(2,6-dichlorobenzyloxy)ethyl2-[4-(benzothiazol-2-yloxy)phenoxy]propionate as a viscous oily productrepresented by the formula above.

n_(D) ²⁵ =1.6125.

In substantially the same manner as described in Example 1, there wereobtained the compounds according to the invention which are shown in thefollowing Table 1.

                                      TABLE 1                                     __________________________________________________________________________     ##STR25##                                                  (I)               Compound No.                                                                           R.sup.1 R.sup.2                                                                           R.sup.3                                                                            X         n  R.sup.4                                                                            m  Y  R.sup.5                                                                           Physical                __________________________________________________________________________                                                          constant                 2       2-Cl    H   H    O         1  H    0  O  H   n.sub.D.sup.25                                                                1.5670                   3       4-Cl    H   H    O         1  H    0  O  H   n.sub.D.sup.25                                                                2.5665                   4       2-Cl    6-Cl                                                                              H    O         1  H    0  O  H   n.sub.D.sup.25                                                                1.5915                   5       2-F     H   H    O         1  H    0  O  H   n.sub.D.sup.25                                                                1.5460                   6       2-CH.sub.3                                                                            H   H    O         1  H    0  O  H   n.sub.D.sup.20                                                                1.5535                   7       3-NO.sub.2                                                                            H   H    O         1  H    0  O  H   n.sub.D.sup.25                                                                1.5750                   8       H       H   H                                                                                   ##STR26##                                                                              1  H    0  O  H   n.sub.D.sup.25                                                                1.5560                   9       H       H   H    O         1  H    0  S  H   n.sub.D.sup.25                                                                1.5863                  10       H       H   H    O         1  H    0  S  6-Cl                                                                              n.sub.D.sup.25                                                                1.5903                  11       2-F     H   H    O         1  H    o  S  H   n.sub.D.sup.25                                                                1.5840                  12       2-Cl    6-Cl                                                                              H    O         1  H    0  S  H   n.sub.D.sup.25                                                                1.6135                  13       H       H   CH.sub.3                                                                           O         1  H    0  S  H   n.sub.D.sup.25                                                                1.586                   14       H       H   H    O         1  H    1  S  H   n.sub.D.sup.25                                                                1.5750                  15       H       H   H    O         1  CH.sub.3                                                                           0  S  H   n.sub.D.sup.25                                                                1.5872                  16       H       H   H    O         2  H    0  S  H   n.sub.D.sup.25                                                                1.5820                  17       H       H   H    S         1  H    0  S  H   n.sub.D.sup.25                                                                1.6130                  18       2-Cl    H   H    S         1  H    0  S  H   n.sub.D.sup.25                                                                1.6192                  19       2-Cl    H   H    SO.sub.2  1  H    0  S  H   n.sub.D.sup.25                                                                1.6300                  20       H       H   H                                                                                   ##STR27##                                                                              1  H    1  S  H   n.sub.D.sup.25                                                                1.5910                  21       H       H   H    NCH(CH.sub.3).sub.2                                                                     1  H    1  S  H   n.sub.D.sup.25                                                                1.5918                  22                                                                                      ##STR28##  H    O         1  H    0  O  H   n.sub.D.sup.25                                                                1.5995                  23                                                                                      ##STR29##  H    O         1  H    0  S  H   n.sub.D.sup.25                                                                1.6226                  __________________________________________________________________________

In the following Examples, the compounds according to the presentinvention are each identified by the number of the correspondingpreparative Example. References to "parts" are to be understood asmeaning parts by weight

EXAMPLE 2 (WETTABLE POWDER)

Fifteen parts of compound No. 6 of the invention, 80 parts of a 1:5mixture of powdery diatomaceous earth and powdery clay, 2 parts ofsodium alkylbenzenesulfonate, and 3 parts of a sodiumalkylnaphthalenesulfonate/formaldehyde condensate are pulverized andmixed to form a wettable powder. It is diluted with water and sprayedonto weeds and/or their habitat.

EXAMPLE 3 (EMULSIFIABLE CONCENTRATE)

Thirty parts of compound No. 11 of the invention, 55 parts of xylene, 8parts of polyoxyethylene alkyl phenyl ether and 7 parts of calciumalkylbenzenesulfonate are mixed with stirring to form an emulsifiableconcentrate. It is diluted with water and sprayed onto weeds and/ortheir habitat.

EXAMPLE 4 (DUST)

Two parts of compound No. 5 of the invention and 98 parts of powderyclay are pulverized and mixed to form a dust. It is scattered over weedsand/or their habitat.

EXAMPLE 5 (GRANULES)

25 parts of water are added to a mixture consisting of 10 parts ofcompound No. 8 of the invention, 30 parts of bentonite(montmorillonite), 58 parts of talc and 2 parts of a lignosulfonate, andthey are well kneaded. The mixture is processed by an extrusion-typegranulating machine to form granules having a size of 10 to 40 meshwhich are then dried at 40° to 50° C. to form granules. The granules arescattered over weeds and/or their habitat.

EXAMPLE 6 (GRANULES)

Ninety-five parts of clay mineral particles having a particle sizedistribution between 0.2 and 2 mm are put in a rotary mixer, and withrotation, 5 parts of the oily compound No. 15 of the invention issprayed onto the particles to wet them uniformly to form granules. Thegranules are scattered over weeds and/or their habitat.

The herbicidal activity of the compounds of the formula (I) isillustrated by the following biotest Example.

The known comparison compound is identified as follows: ##STR30## (knownfrom U.S. Pat. No. 4,130,413)

EXAMPLE 7 (BIOLOGICAL TEST)

Test of foliar/soil treatment of aquatic paddy weeds under irrigation(pot test):

Formulation of an active compound

Carrier: 5 parts by weight of acetone

Emulsifier: 1 part by weight of benzyloxyglycol ether

A preparation containing the active compound is formed by mixing 1 partby weight of each of the active compounds with the carrier andemulsifier in the amounts indicated above, and diluting a predeterminedamount of the resulting emulsifiable concentrate with water.

Testing procedure

Aquatic paddy soil was filled in Wagner pots (1/5,000 ares), and riceseedlings (variety: Kinnampu) in the 2- to 3-leaf stage (plant heightabout 10 cm) were transplanted at a rate of 2 per pot. Seeds ofEchinochloa Crus-galli P. Beauv. var oryzicola Ohwi, Echinochloacrus-galli P. Beauv. var. caudata Kitagawa, Sacciolepis indica Chasevar. oryzetorum Ohwi and Panicum bisulcatum Thunb. were inoculated inthe pots. The soil in the pots was maintained in the wet state. AfterEchinochloa crus-galli P. Beauv. var. oryzicola Ohwi grew to a stage ofapproximately two leaves (about 7 to 9 days after sowing), each pot waswatered to a depth of about 6 cm. A predetermined amount of the compoundof this invention in the form of an emulsion was applied by means of apipette to treat each pot. After the treatment, the pots were subjectedto a water leaking treatment for 2 days at a rate of 2 to 3 cm per day,and thereafter maintained in the watered state to a depth of about 3 cm.Four weeks after the treatment the herbicidal effect and the degree ofphytotoxicity were evaluated on a scale of from 0 to 5 as follows:

Evaluation of the herbicidal effect (herbicidal rate based on thenon-treated area):

5: at least 95% (withered)

4: at least 80% but less than 95%

3: at least 50% but less than 80%

2: at least 30% but less than 50%

1: at least 10% but less than 30%

0: less than 10% (no effect)

Evaluation of phytotoxicity to aquatic rice plants (the phytotoxicityrate based on the non-treated area):

5: at least 90% (fatal injury)

4: at least 50% but less than 90%

3: at least 30% but less than 50%

2: at least 10% but less than 30%

1: more than 0% but less than 10%

0: 0% (no phytotoxicity)

The test results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                 Amount of                                                                     the active                  Phyto-                                   Compound ingredient  Herbicidal effect                                                                             toxicity                                 No.      (kg/ha)     A     B     C   D     to rice                            ______________________________________                                         1       1.0         5     5     5   5     0                                   5       1.0         5     5     5   5     0                                   6       1.0         5     5     5   5     0                                  11       1.0         5     5     5   5     0                                  12       1.0         5     5     5   5     0                                  15       0.5         5     5     5   5     0                                  16       0.5         5     5     5   5     0                                  18       1.0         5     5     5   5     0                                  21       1.0         5     5     5   5     0                                  Comparison                                                                             1.0         5     5     5   5     4                                  A-1      0.5         5     5     5   5     3                                           0.1         3     3     4   4     2                                  ______________________________________                                         A: Echinochloa crusgalli P. Beauv. var. oryzicola Ohwi,                       B: Echinochloa crusgalli P. Beauv. var. caudata Kitagawa,                     C: Sacciolepis indica Chase var. oryzetorum Ohwi,                             D: Panicum bisulcatum Thunb.                                             

What is claimed is:
 1. Substituted phenoxyalkanecarboxylic acid estersof the formula ##STR31## in which R¹ and R², independently of oneanother, represent a hydrogen atom, a halogen atom, a lower alkyl groupor a nitro group, orR¹ and R², together with the benzene ring to whichthey are bonded, represent a naphthalene ring, R³ and R⁴, independentlyof one another, represent a hydrogen atom or a methyl group, nrepresents 1 or 2, m represents 0 or 1, X represents an oxygen atom, asulfur atom, a sulfonyl group of a group of the formula ##STR32## inwhich R⁶ represents a lower alkyl group, R⁵ represents a hydrogen atomor a halogen atom, and Y represents an oxygen atom or a sulfur atom. 2.Substituted phenoxyalkanecarboxylic acid ester as claimed in claim 1,whereinR¹ is hydrogen, fluorine, chlorine, bromine, iodine, alkyl with 1to 4 carbon atoms or nitro.
 3. Substituted phenoxyalkanecarboxylic acidester as claimed in claim 1, whereinR² is hydrogen, fluorine, chlorine,bromine, iodine, alkyl with 1 to 4 carbon atoms or nitro.
 4. Substitutedphenoxyalkanecarboxylic acid ester as claimed in claim 1, whereinR¹ andR², together with the benzene ring to which they are bonded, form anaphthalene ring.
 5. Substituted phenoxyalkanecarboxylic acid ester asclaimed in claim 1, whereinX is oxygen, sulfur, sulfonyl or a group ofthe formula ##STR33## in which R⁶ is alkyl with 1 to 4 carbon atoms, R⁵is hydrogen, fluorine, chlorine, bromine and iodine, and Y is oxygen orsulfur.
 6. Substituted phenoxyalkanecarboxylic acid ester as claimed inclaim 1, whereinR¹ is hydrogen, fluorine, chlorine, bromine, methyl,ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec.-butyl, tert.-butylor nitro, R² is hydrogen, fluorine, chlorine, bromine, methyl, ethyl,n-propyl, isopropyl, n-butyl, iso-butyl, sec.-butyl, tert.-butyl ornitro, or R¹ and R², together with the benzene ring to which they arebonded, are a naphthalene ring, R³ is hydrogen or methyl, R⁴ is hydrogenor methyl, m is 0 or 1, n is 1 or 2, X is oxygen, sulfur, sulfonyl or agroup of the formula ##STR34## in which R⁶ is methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl, sec-butyl or tert.-butyl, R⁵ ishydrogen, fluorine, chlorine and bromine, and Y is oxygen or sulfur. 7.Substituted phenoxyalkanecarboxylic acid ester as claimed in claim 1,designated by the formula ##STR35##
 8. Substitutedphenoxyalkanecarboxylic acid ester as claimed in claim 1, designated bythe formula ##STR36##
 9. Substituted phenoxyalkanecarboxylic acid esteras claimed in claim 1, designated by the formula ##STR37## 10.Substituted phenoxyalkanecarboxylic acid ester as claimed in claim 1,designated by the formula ##STR38##
 11. Substitutedphenoxyalkanecarboxylic acid ester as claimed in claim 1, designated bythe formula ##STR39##
 12. Substituted phenoxyalkanecarboxylic acid esteras claimed in claim 1, designated by the formula ##STR40##
 13. Aherbicidal composition comprising an agriculturally acceptable carrierand, in herbicidally effective amount, a substitutedphenoxyalkanecarboxylic acid ester as claimed in claim
 1. 14. Aherbicidal composition as claimed in claim 13 containing the ester infrom 0.01 to 95% by weight.
 15. A method of combating weeds whichcomprises applying to the weeds, or their habitat, a herbicidallyeffective amount of a phenoxyalkanecarboxylic acid ester as claimed inclaim
 1. 16. A method as claimed in claim 15, wherein said compound isapplied at a dosage of 0.1 to 5.0 kg per hectare.
 17. A method asclaimed in claim 16, wherein said compound is applied at a dosage of 0.2to 2.0 kg per hectare.
 18. A method as claimed in claim 15, wherein saidphenoxyalkanecarboxylic acid ester is ##STR41##
 19. Substitutedphenoxyalkanecarboxylic acid ester as claimed in claim 1, of the formula##STR42## in which R¹, R² and R⁵ each independently is a hydrogen atomor a halogen atoms, orR¹ and R² together with the benzene ring to whichthey are bonded, represent a naphthalene ring, and X and Y each is anoxygen or sulfur atom.